Lives Lost to Leishmaniasis: New analysis of Brazilian disease burden

When researchers identify diseases that pose the greatest threat to health, it helps policymakers and specialists fine-tune the effectiveness of national disease control measures. One common tropical disease, leishmaniasis, is transferred by sandfly bites and can cause permanent injury, disability or death. In Brazil, cutaneous and mucocutaneous leishmaniasis (CML) and the most serious form of the disease, visceral leishmaniasis (VL), affect thousands of people annually. While leishmaniasis impacts have been studied in Brazil at a national level, regional analyses were missing.

To address this gap, Dr. Juliana Maria Trindade Bezerra of Universidade Federal de Minas Gerais and colleagues analyzed the raw data generated by the 2016 Global Burden of Diseases Study (GBD). In their new PLOS Neglected Tropical Diseases article, the authors estimate the burden of VL and CML in Brazil’s 26 states and its one federal district from 1990 to 2016. Their study is the first analysis of Brazilian VL and CML to be grouped by assigned sex (male and female), age, and region.

The authors report that the rate of Brazilian leishmaniasis infections decreased by 48.5 percent over the study period, mostly due to a drop in the overall rate of CML infection. However, the measure of overall health loss (due to early death or symptoms) increased by 83.6 percent. Notably, the number of new VL cases increased by 52.9 percent, and an even higher increase was seen in children under the age of 1. There was a higher disease burden for assigned males than for assigned females, though both showed an increase in fatalities. The authors also note an increase in infections in the North, Midwest, and Southeast – likely due to urbanization, poverty, the presence of migrants in the urban peripheries, and migration due to drought.

The authors note that the next study should include more data-gathering and case-recording in the North and Northeast regions. They also note that the next study should be more stratified, allowing analysis of the different impacts of and responses to cutaneous, mucocutaneous, and mucosal leishmaniasis during infection and treatment.

“…[T]he observed regional variations reinforce the need to implement policies adapted to the reality of each region. The regional trends of life years lost due to death and incapacity caused by leishmaniasis should be carefully analyzed with the purpose of adopting control strategies specific to the realities of the different Brazilian federated units,” the authors conclude.